/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.feilong.lib.beanutils;

import java.lang.ref.Reference;
import java.lang.ref.WeakReference;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.Collections;
import java.util.Map;
import java.util.WeakHashMap;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * <p>
 * Utility reflection methods focused on methods in general rather than properties in particular.
 * </p>
 *
 * <h3>Known Limitations</h3>
 * <h4>Accessing Public Methods In A Default Access Superclass</h4>
 * <p>
 * There is an issue when invoking public methods contained in a default access superclass.
 * Reflection locates these methods fine and correctly assigns them as public.
 * However, an <code>IllegalAccessException</code> is thrown if the method is invoked.
 * </p>
 *
 * <p>
 * <code>MethodUtils</code> contains a workaround for this situation.
 * It will attempt to call <code>setAccessible</code> on this method.
 * If this call succeeds, then the method can be invoked as normal.
 * This call will only succeed when the application has sufficient security privilages.
 * If this call fails then a warning will be logged and the method may fail.
 * </p>
 *
 * @version $Id$
 * @deprecated may be can use com.feilong.lib.lang3.reflect.MethodUtils
 */
@Deprecated
public class MethodUtils{

    /** The Constant log. */
    private static final Logger                                   LOGGER                  = LoggerFactory.getLogger(MethodUtils.class);

    // --------------------------------------------------------- Private Methods

    /**
     * Only log warning about accessibility work around once.
     * <p>
     * Note that this is broken when this class is deployed via a shared
     * classloader in a container, as the warning message will be emitted
     * only once, not once per webapp. However making the warning appear
     * once per webapp means having a map keyed by context classloader
     * which introduces nasty memory-leak problems. As this warning is
     * really optional we can ignore this problem; only one of the webapps
     * will get the warning in its logs but that should be good enough.
     */
    private static boolean                                        loggedAccessibleWarning = false;

    /**
     * Indicates whether methods should be cached for improved performance.
     * <p>
     * Note that when this class is deployed via a shared classloader in
     * a container, this will affect all webapps. However making this
     * configurable per webapp would mean having a map keyed by context classloader
     * which may introduce memory-leak problems.
     */
    private static boolean                                        CACHE_METHODS           = true;

    /** An empty class array */
    private static final Class<?>[]                               EMPTY_CLASS_PARAMETERS  = new Class[0];

    /** An empty object array */
    private static final Object[]                                 EMPTY_OBJECT_ARRAY      = new Object[0];

    /**
     * Stores a cache of MethodDescriptor -> Method in a WeakHashMap.
     * <p>
     * The keys into this map only ever exist as temporary variables within
     * methods of this class, and are never exposed to users of this class.
     * This means that the WeakHashMap is used only as a mechanism for
     * limiting the size of the cache, ie a way to tell the garbage collector
     * that the contents of the cache can be completely garbage-collected
     * whenever it needs the memory. Whether this is a good approach to
     * this problem is doubtful; something like the commons-collections
     * LRUMap may be more appropriate (though of course selecting an
     * appropriate size is an issue).
     * <p>
     * This static variable is safe even when this code is deployed via a
     * shared classloader because it is keyed via a MethodDescriptor object
     * which has a Class as one of its members and that member is used in
     * the MethodDescriptor.equals method. So two components that load the same
     * class via different classloaders will generate non-equal MethodDescriptor
     * objects and hence end up with different entries in the map.
     */
    private static final Map<MethodDescriptor, Reference<Method>> cache                   = Collections
                    .synchronizedMap(new WeakHashMap<MethodDescriptor, Reference<Method>>());

    // --------------------------------------------------------- Public Methods

    /**
     * Set whether methods should be cached for greater performance or not,
     * default is <code>true</code>.
     *
     * @param cacheMethods
     *            <code>true</code> if methods should be
     *            cached for greater performance, otherwise <code>false</code>
     * @since 1.8.0
     */
    public static synchronized void setCacheMethods(final boolean cacheMethods){
        CACHE_METHODS = cacheMethods;
        if (!CACHE_METHODS){
            clearCache();
        }
    }

    /**
     * Clear the method cache.
     * 
     * @return the number of cached methods cleared
     * @since 1.8.0
     */
    public static synchronized int clearCache(){
        final int size = cache.size();
        cache.clear();
        return size;
    }

    /**
     * <p>
     * Invoke a named method whose parameter type matches the object type.
     * </p>
     *
     * <p>
     * The behaviour of this method is less deterministic
     * than <code>invokeExactMethod()</code>.
     * It loops through all methods with names that match
     * and then executes the first it finds with compatible parameters.
     * </p>
     *
     * <p>
     * This method supports calls to methods taking primitive parameters
     * via passing in wrapping classes. So, for example, a <code>Boolean</code> class
     * would match a <code>boolean</code> primitive.
     * </p>
     *
     * <p>
     * This is a convenient wrapper for
     * {@link #invokeMethod(Object object,String methodName,Object [] args)}.
     * </p>
     *
     * @param object
     *            invoke method on this object
     * @param methodName
     *            get method with this name
     * @param arg
     *            use this argument. May be null (this will result in calling the
     *            parameterless method with name {@code methodName}).
     * @return The value returned by the invoked method
     *
     * @throws NoSuchMethodException
     *             if there is no such accessible method
     * @throws InvocationTargetException
     *             wraps an exception thrown by the
     *             method invoked
     * @throws IllegalAccessException
     *             if the requested method is not accessible
     *             via reflection
     */
    public static Object invokeMethod(final Object object,final String methodName,final Object arg)
                    throws NoSuchMethodException,IllegalAccessException,InvocationTargetException{

        final Object[] args = toArray(arg);
        return invokeMethod(object, methodName, args);
    }

    /**
     * <p>
     * Invoke a named method whose parameter type matches the object type.
     * </p>
     *
     * <p>
     * The behaviour of this method is less deterministic
     * than {@link #invokeExactMethod(Object object,String methodName,Object [] args)}.
     * It loops through all methods with names that match
     * and then executes the first it finds with compatible parameters.
     * </p>
     *
     * <p>
     * This method supports calls to methods taking primitive parameters
     * via passing in wrapping classes. So, for example, a <code>Boolean</code> class
     * would match a <code>boolean</code> primitive.
     * </p>
     *
     * <p>
     * This is a convenient wrapper for
     * {@link #invokeMethod(Object object,String methodName,Object [] args,Class[] parameterTypes)}.
     * </p>
     *
     * @param object
     *            invoke method on this object
     * @param methodName
     *            get method with this name
     * @param args
     *            use these arguments - treat null as empty array (passing null will
     *            result in calling the parameterless method with name {@code methodName}).
     * @return The value returned by the invoked method
     *
     * @throws NoSuchMethodException
     *             if there is no such accessible method
     * @throws InvocationTargetException
     *             wraps an exception thrown by the
     *             method invoked
     * @throws IllegalAccessException
     *             if the requested method is not accessible
     *             via reflection
     */
    public static Object invokeMethod(final Object object,final String methodName,Object[] args)
                    throws NoSuchMethodException,IllegalAccessException,InvocationTargetException{

        if (args == null){
            args = EMPTY_OBJECT_ARRAY;
        }
        final int arguments = args.length;
        final Class<?>[] parameterTypes = new Class[arguments];
        for (int i = 0; i < arguments; i++){
            parameterTypes[i] = args[i].getClass();
        }
        return invokeMethod(object, methodName, args, parameterTypes);
    }

    /**
     * <p>
     * Invoke a named method whose parameter type matches the object type.
     * </p>
     *
     * <p>
     * The behaviour of this method is less deterministic
     * than {@link
     * #invokeExactMethod(Object object,String methodName,Object [] args,Class[] parameterTypes)}.
     * It loops through all methods with names that match
     * and then executes the first it finds with compatible parameters.
     * </p>
     *
     * <p>
     * This method supports calls to methods taking primitive parameters
     * via passing in wrapping classes. So, for example, a <code>Boolean</code> class
     * would match a <code>boolean</code> primitive.
     * </p>
     *
     *
     * @param object
     *            invoke method on this object
     * @param methodName
     *            get method with this name
     * @param args
     *            use these arguments - treat null as empty array (passing null will
     *            result in calling the parameterless method with name {@code methodName}).
     * @param parameterTypes
     *            match these parameters - treat null as empty array
     * @return The value returned by the invoked method
     *
     * @throws NoSuchMethodException
     *             if there is no such accessible method
     * @throws InvocationTargetException
     *             wraps an exception thrown by the
     *             method invoked
     * @throws IllegalAccessException
     *             if the requested method is not accessible
     *             via reflection
     */
    public static Object invokeMethod(final Object object,final String methodName,Object[] args,Class<?>[] parameterTypes)
                    throws NoSuchMethodException,IllegalAccessException,InvocationTargetException{

        if (parameterTypes == null){
            parameterTypes = EMPTY_CLASS_PARAMETERS;
        }
        if (args == null){
            args = EMPTY_OBJECT_ARRAY;
        }

        final Method method = getMatchingAccessibleMethod(object.getClass(), methodName, parameterTypes);
        if (method == null){
            throw new NoSuchMethodException("No such accessible method: " + methodName + "() on object: " + object.getClass().getName());
        }
        return method.invoke(object, args);
    }

    /**
     * <p>
     * Invoke a method whose parameter type matches exactly the object
     * type.
     * </p>
     *
     * <p>
     * This is a convenient wrapper for
     * {@link #invokeExactMethod(Object object,String methodName,Object [] args)}.
     * </p>
     *
     * @param object
     *            invoke method on this object
     * @param methodName
     *            get method with this name
     * @param arg
     *            use this argument. May be null (this will result in calling the
     *            parameterless method with name {@code methodName}).
     * @return The value returned by the invoked method
     *
     * @throws NoSuchMethodException
     *             if there is no such accessible method
     * @throws InvocationTargetException
     *             wraps an exception thrown by the
     *             method invoked
     * @throws IllegalAccessException
     *             if the requested method is not accessible
     *             via reflection
     */
    public static Object invokeExactMethod(final Object object,final String methodName,final Object arg)
                    throws NoSuchMethodException,IllegalAccessException,InvocationTargetException{

        final Object[] args = toArray(arg);
        return invokeExactMethod(object, methodName, args);
    }

    /**
     * <p>
     * Invoke a method whose parameter types match exactly the object
     * types.
     * </p>
     *
     * <p>
     * This uses reflection to invoke the method obtained from a call to
     * <code>getAccessibleMethod()</code>.
     * </p>
     *
     * @param object
     *            invoke method on this object
     * @param methodName
     *            get method with this name
     * @param args
     *            use these arguments - treat null as empty array (passing null will
     *            result in calling the parameterless method with name {@code methodName}).
     * @return The value returned by the invoked method
     *
     * @throws NoSuchMethodException
     *             if there is no such accessible method
     * @throws InvocationTargetException
     *             wraps an exception thrown by the
     *             method invoked
     * @throws IllegalAccessException
     *             if the requested method is not accessible
     *             via reflection
     */
    public static Object invokeExactMethod(final Object object,final String methodName,Object[] args)
                    throws NoSuchMethodException,IllegalAccessException,InvocationTargetException{

        if (args == null){
            args = EMPTY_OBJECT_ARRAY;
        }
        final int arguments = args.length;
        final Class<?>[] parameterTypes = new Class[arguments];
        for (int i = 0; i < arguments; i++){
            parameterTypes[i] = args[i].getClass();
        }
        return invokeExactMethod(object, methodName, args, parameterTypes);
    }

    /**
     * <p>
     * Invoke a method whose parameter types match exactly the parameter
     * types given.
     * </p>
     *
     * <p>
     * This uses reflection to invoke the method obtained from a call to
     * <code>getAccessibleMethod()</code>.
     * </p>
     *
     * @param object
     *            invoke method on this object
     * @param methodName
     *            get method with this name
     * @param args
     *            use these arguments - treat null as empty array (passing null will
     *            result in calling the parameterless method with name {@code methodName}).
     * @param parameterTypes
     *            match these parameters - treat null as empty array
     * @return The value returned by the invoked method
     *
     * @throws NoSuchMethodException
     *             if there is no such accessible method
     * @throws InvocationTargetException
     *             wraps an exception thrown by the
     *             method invoked
     * @throws IllegalAccessException
     *             if the requested method is not accessible
     *             via reflection
     */
    public static Object invokeExactMethod(final Object object,final String methodName,Object[] args,Class<?>[] parameterTypes)
                    throws NoSuchMethodException,IllegalAccessException,InvocationTargetException{

        if (args == null){
            args = EMPTY_OBJECT_ARRAY;
        }

        if (parameterTypes == null){
            parameterTypes = EMPTY_CLASS_PARAMETERS;
        }

        final Method method = getAccessibleMethod(object.getClass(), methodName, parameterTypes);
        if (method == null){
            throw new NoSuchMethodException("No such accessible method: " + methodName + "() on object: " + object.getClass().getName());
        }
        return method.invoke(object, args);
    }

    /**
     * <p>
     * Invoke a static method whose parameter types match exactly the parameter
     * types given.
     * </p>
     *
     * <p>
     * This uses reflection to invoke the method obtained from a call to
     * {@link #getAccessibleMethod(Class, String, Class[])}.
     * </p>
     *
     * @param objectClass
     *            invoke static method on this class
     * @param methodName
     *            get method with this name
     * @param args
     *            use these arguments - treat null as empty array (passing null will
     *            result in calling the parameterless method with name {@code methodName}).
     * @param parameterTypes
     *            match these parameters - treat null as empty array
     * @return The value returned by the invoked method
     *
     * @throws NoSuchMethodException
     *             if there is no such accessible method
     * @throws InvocationTargetException
     *             wraps an exception thrown by the
     *             method invoked
     * @throws IllegalAccessException
     *             if the requested method is not accessible
     *             via reflection
     * @since 1.8.0
     */
    public static Object invokeExactStaticMethod(final Class<?> objectClass,final String methodName,Object[] args,Class<?>[] parameterTypes)
                    throws NoSuchMethodException,IllegalAccessException,InvocationTargetException{

        if (args == null){
            args = EMPTY_OBJECT_ARRAY;
        }

        if (parameterTypes == null){
            parameterTypes = EMPTY_CLASS_PARAMETERS;
        }

        final Method method = getAccessibleMethod(objectClass, methodName, parameterTypes);
        if (method == null){
            throw new NoSuchMethodException("No such accessible method: " + methodName + "() on class: " + objectClass.getName());
        }
        return method.invoke(null, args);
    }

    /**
     * <p>
     * Invoke a named static method whose parameter type matches the object type.
     * </p>
     *
     * <p>
     * The behaviour of this method is less deterministic
     * than {@link #invokeExactMethod(Object, String, Object[], Class[])}.
     * It loops through all methods with names that match
     * and then executes the first it finds with compatible parameters.
     * </p>
     *
     * <p>
     * This method supports calls to methods taking primitive parameters
     * via passing in wrapping classes. So, for example, a <code>Boolean</code> class
     * would match a <code>boolean</code> primitive.
     * </p>
     *
     * <p>
     * This is a convenient wrapper for
     * {@link #invokeStaticMethod(Class objectClass,String methodName,Object [] args)}.
     * </p>
     *
     * @param objectClass
     *            invoke static method on this class
     * @param methodName
     *            get method with this name
     * @param arg
     *            use this argument. May be null (this will result in calling the
     *            parameterless method with name {@code methodName}).
     * @return The value returned by the invoked method
     *
     * @throws NoSuchMethodException
     *             if there is no such accessible method
     * @throws InvocationTargetException
     *             wraps an exception thrown by the
     *             method invoked
     * @throws IllegalAccessException
     *             if the requested method is not accessible
     *             via reflection
     * @since 1.8.0
     */
    public static Object invokeStaticMethod(final Class<?> objectClass,final String methodName,final Object arg)
                    throws NoSuchMethodException,IllegalAccessException,InvocationTargetException{

        final Object[] args = toArray(arg);
        return invokeStaticMethod(objectClass, methodName, args);
    }

    /**
     * <p>
     * Invoke a named static method whose parameter type matches the object type.
     * </p>
     *
     * <p>
     * The behaviour of this method is less deterministic
     * than {@link #invokeExactMethod(Object object,String methodName,Object [] args)}.
     * It loops through all methods with names that match
     * and then executes the first it finds with compatible parameters.
     * </p>
     *
     * <p>
     * This method supports calls to methods taking primitive parameters
     * via passing in wrapping classes. So, for example, a <code>Boolean</code> class
     * would match a <code>boolean</code> primitive.
     * </p>
     *
     * <p>
     * This is a convenient wrapper for
     * {@link #invokeStaticMethod(Class objectClass,String methodName,Object [] args,Class[] parameterTypes)}.
     * </p>
     *
     * @param objectClass
     *            invoke static method on this class
     * @param methodName
     *            get method with this name
     * @param args
     *            use these arguments - treat null as empty array (passing null will
     *            result in calling the parameterless method with name {@code methodName}).
     * @return The value returned by the invoked method
     *
     * @throws NoSuchMethodException
     *             if there is no such accessible method
     * @throws InvocationTargetException
     *             wraps an exception thrown by the
     *             method invoked
     * @throws IllegalAccessException
     *             if the requested method is not accessible
     *             via reflection
     * @since 1.8.0
     */
    public static Object invokeStaticMethod(final Class<?> objectClass,final String methodName,Object[] args)
                    throws NoSuchMethodException,IllegalAccessException,InvocationTargetException{

        if (args == null){
            args = EMPTY_OBJECT_ARRAY;
        }
        final int arguments = args.length;
        final Class<?>[] parameterTypes = new Class[arguments];
        for (int i = 0; i < arguments; i++){
            parameterTypes[i] = args[i].getClass();
        }
        return invokeStaticMethod(objectClass, methodName, args, parameterTypes);
    }

    /**
     * <p>
     * Invoke a named static method whose parameter type matches the object type.
     * </p>
     *
     * <p>
     * The behaviour of this method is less deterministic
     * than {@link
     * #invokeExactStaticMethod(Class objectClass,String methodName,Object [] args,Class[] parameterTypes)}.
     * It loops through all methods with names that match
     * and then executes the first it finds with compatible parameters.
     * </p>
     *
     * <p>
     * This method supports calls to methods taking primitive parameters
     * via passing in wrapping classes. So, for example, a <code>Boolean</code> class
     * would match a <code>boolean</code> primitive.
     * </p>
     *
     *
     * @param objectClass
     *            invoke static method on this class
     * @param methodName
     *            get method with this name
     * @param args
     *            use these arguments - treat null as empty array (passing null will
     *            result in calling the parameterless method with name {@code methodName}).
     * @param parameterTypes
     *            match these parameters - treat null as empty array
     * @return The value returned by the invoked method
     *
     * @throws NoSuchMethodException
     *             if there is no such accessible method
     * @throws InvocationTargetException
     *             wraps an exception thrown by the
     *             method invoked
     * @throws IllegalAccessException
     *             if the requested method is not accessible
     *             via reflection
     * @since 1.8.0
     */
    public static Object invokeStaticMethod(final Class<?> objectClass,final String methodName,Object[] args,Class<?>[] parameterTypes)
                    throws NoSuchMethodException,IllegalAccessException,InvocationTargetException{

        if (parameterTypes == null){
            parameterTypes = EMPTY_CLASS_PARAMETERS;
        }
        if (args == null){
            args = EMPTY_OBJECT_ARRAY;
        }

        final Method method = getMatchingAccessibleMethod(objectClass, methodName, parameterTypes);
        if (method == null){
            throw new NoSuchMethodException("No such accessible method: " + methodName + "() on class: " + objectClass.getName());
        }
        return method.invoke(null, args);
    }

    /**
     * <p>
     * Invoke a static method whose parameter type matches exactly the object
     * type.
     * </p>
     *
     * <p>
     * This is a convenient wrapper for
     * {@link #invokeExactStaticMethod(Class objectClass,String methodName,Object [] args)}.
     * </p>
     *
     * @param objectClass
     *            invoke static method on this class
     * @param methodName
     *            get method with this name
     * @param arg
     *            use this argument. May be null (this will result in calling the
     *            parameterless method with name {@code methodName}).
     * @return The value returned by the invoked method
     *
     * @throws NoSuchMethodException
     *             if there is no such accessible method
     * @throws InvocationTargetException
     *             wraps an exception thrown by the
     *             method invoked
     * @throws IllegalAccessException
     *             if the requested method is not accessible
     *             via reflection
     * @since 1.8.0
     */
    public static Object invokeExactStaticMethod(final Class<?> objectClass,final String methodName,final Object arg)
                    throws NoSuchMethodException,IllegalAccessException,InvocationTargetException{

        final Object[] args = toArray(arg);
        return invokeExactStaticMethod(objectClass, methodName, args);
    }

    /**
     * <p>
     * Invoke a static method whose parameter types match exactly the object
     * types.
     * </p>
     *
     * <p>
     * This uses reflection to invoke the method obtained from a call to
     * {@link #getAccessibleMethod(Class, String, Class[])}.
     * </p>
     *
     * @param objectClass
     *            invoke static method on this class
     * @param methodName
     *            get method with this name
     * @param args
     *            use these arguments - treat null as empty array (passing null will
     *            result in calling the parameterless method with name {@code methodName}).
     * @return The value returned by the invoked method
     *
     * @throws NoSuchMethodException
     *             if there is no such accessible method
     * @throws InvocationTargetException
     *             wraps an exception thrown by the
     *             method invoked
     * @throws IllegalAccessException
     *             if the requested method is not accessible
     *             via reflection
     * @since 1.8.0
     */
    public static Object invokeExactStaticMethod(final Class<?> objectClass,final String methodName,Object[] args)
                    throws NoSuchMethodException,IllegalAccessException,InvocationTargetException{

        if (args == null){
            args = EMPTY_OBJECT_ARRAY;
        }
        final int arguments = args.length;
        final Class<?>[] parameterTypes = new Class[arguments];
        for (int i = 0; i < arguments; i++){
            parameterTypes[i] = args[i].getClass();
        }
        return invokeExactStaticMethod(objectClass, methodName, args, parameterTypes);
    }

    private static Object[] toArray(final Object arg){
        Object[] args = null;
        if (arg != null){
            args = new Object[] { arg };
        }
        return args;
    }

    /**
     * <p>
     * Return an accessible method (that is, one that can be invoked via
     * reflection) with given name and a single parameter. If no such method
     * can be found, return <code>null</code>.
     * Basically, a convenience wrapper that constructs a <code>Class</code>
     * array for you.
     * </p>
     *
     * @param clazz
     *            get method from this class
     * @param methodName
     *            get method with this name
     * @param parameterType
     *            taking this type of parameter
     * @return The accessible method
     */
    public static Method getAccessibleMethod(final Class<?> clazz,final String methodName,final Class<?> parameterType){

        final Class<?>[] parameterTypes = { parameterType };
        return getAccessibleMethod(clazz, methodName, parameterTypes);
    }

    /**
     * <p>
     * Return an accessible method (that is, one that can be invoked via
     * reflection) with given name and parameters. If no such method
     * can be found, return <code>null</code>.
     * This is just a convenient wrapper for
     * {@link #getAccessibleMethod(Method method)}.
     * </p>
     *
     * @param clazz
     *            get method from this class
     * @param methodName
     *            get method with this name
     * @param parameterTypes
     *            with these parameters types
     * @return The accessible method
     */
    public static Method getAccessibleMethod(final Class<?> clazz,final String methodName,final Class<?>[] parameterTypes){

        try{
            final MethodDescriptor md = new MethodDescriptor(clazz, methodName, parameterTypes, true);
            // Check the cache first
            Method method = getCachedMethod(md);
            if (method != null){
                return method;
            }

            method = getAccessibleMethod(clazz, clazz.getMethod(methodName, parameterTypes));
            cacheMethod(md, method);
            return method;
        }catch (final NoSuchMethodException e){
            return (null);
        }
    }

    /**
     * <p>
     * Return an accessible method (that is, one that can be invoked via
     * reflection) that implements the specified Method. If no such method
     * can be found, return <code>null</code>.
     * </p>
     *
     * @param method
     *            The method that we wish to call
     * @return The accessible method
     */
    public static Method getAccessibleMethod(final Method method){

        // Make sure we have a method to check
        if (method == null){
            return (null);
        }

        return getAccessibleMethod(method.getDeclaringClass(), method);
    }

    /**
     * <p>
     * Return an accessible method (that is, one that can be invoked via
     * reflection) that implements the specified Method. If no such method
     * can be found, return <code>null</code>.
     * </p>
     *
     * @param clazz
     *            The class of the object
     * @param method
     *            The method that we wish to call
     * @return The accessible method
     * @since 1.8.0
     */
    public static Method getAccessibleMethod(Class<?> clazz,Method method){

        // Make sure we have a method to check
        if (method == null){
            return (null);
        }

        // If the requested method is not public we cannot call it
        if (!Modifier.isPublic(method.getModifiers())){
            return (null);
        }

        boolean sameClass = true;
        if (clazz == null){
            clazz = method.getDeclaringClass();
        }else{
            sameClass = clazz.equals(method.getDeclaringClass());
            if (!method.getDeclaringClass().isAssignableFrom(clazz)){
                throw new IllegalArgumentException(clazz.getName() + " is not assignable from " + method.getDeclaringClass().getName());
            }
        }

        // If the class is public, we are done
        if (Modifier.isPublic(clazz.getModifiers())){
            if (!sameClass && !Modifier.isPublic(method.getDeclaringClass().getModifiers())){
                setMethodAccessible(method); // Default access superclass workaround
            }
            return (method);
        }

        final String methodName = method.getName();
        final Class<?>[] parameterTypes = method.getParameterTypes();

        // Check the implemented interfaces and subinterfaces
        method = getAccessibleMethodFromInterfaceNest(clazz, methodName, parameterTypes);

        // Check the superclass chain
        if (method == null){
            method = getAccessibleMethodFromSuperclass(clazz, methodName, parameterTypes);
        }

        return (method);
    }

    // -------------------------------------------------------- Private Methods

    /**
     * <p>
     * Return an accessible method (that is, one that can be invoked via
     * reflection) by scanning through the superclasses. If no such method
     * can be found, return <code>null</code>.
     * </p>
     *
     * @param clazz
     *            Class to be checked
     * @param methodName
     *            Method name of the method we wish to call
     * @param parameterTypes
     *            The parameter type signatures
     */
    private static Method getAccessibleMethodFromSuperclass(final Class<?> clazz,final String methodName,final Class<?>[] parameterTypes){

        Class<?> parentClazz = clazz.getSuperclass();
        while (parentClazz != null){
            if (Modifier.isPublic(parentClazz.getModifiers())){
                try{
                    return parentClazz.getMethod(methodName, parameterTypes);
                }catch (final NoSuchMethodException e){
                    return null;
                }
            }
            parentClazz = parentClazz.getSuperclass();
        }
        return null;
    }

    /**
     * <p>
     * Return an accessible method (that is, one that can be invoked via
     * reflection) that implements the specified method, by scanning through
     * all implemented interfaces and subinterfaces. If no such method
     * can be found, return <code>null</code>.
     * </p>
     *
     * <p>
     * There isn't any good reason why this method must be private.
     * It is because there doesn't seem any reason why other classes should
     * call this rather than the higher level methods.
     * </p>
     *
     * @param clazz
     *            Parent class for the interfaces to be checked
     * @param methodName
     *            Method name of the method we wish to call
     * @param parameterTypes
     *            The parameter type signatures
     */
    private static Method getAccessibleMethodFromInterfaceNest(Class<?> clazz,final String methodName,final Class<?>[] parameterTypes){

        Method method = null;

        // Search up the superclass chain
        for (; clazz != null; clazz = clazz.getSuperclass()){

            // Check the implemented interfaces of the parent class
            final Class<?>[] interfaces = clazz.getInterfaces();
            for (Class<?> interface1 : interfaces){

                // Is this interface public?
                if (!Modifier.isPublic(interface1.getModifiers())){
                    continue;
                }

                // Does the method exist on this interface?
                try{
                    method = interface1.getDeclaredMethod(methodName, parameterTypes);
                }catch (final NoSuchMethodException e){
                    /*
                     * Swallow, if no method is found after the loop then this
                     * method returns null.
                     */
                }
                if (method != null){
                    return method;
                }

                // Recursively check our parent interfaces
                method = getAccessibleMethodFromInterfaceNest(interface1, methodName, parameterTypes);
                if (method != null){
                    return method;
                }

            }

        }

        // We did not find anything
        return (null);
    }

    /**
     * <p>
     * Find an accessible method that matches the given name and has compatible parameters.
     * Compatible parameters mean that every method parameter is assignable from
     * the given parameters.
     * In other words, it finds a method with the given name
     * that will take the parameters given.
     * <p>
     *
     * <p>
     * This method is slightly undeterministic since it loops
     * through methods names and return the first matching method.
     * </p>
     *
     * <p>
     * This method is used by
     * {@link
     * #invokeMethod(Object object,String methodName,Object [] args,Class[] parameterTypes)}.
     *
     * <p>
     * This method can match primitive parameter by passing in wrapper classes.
     * For example, a <code>Boolean</code> will match a primitive <code>boolean</code>
     * parameter.
     *
     * @param clazz
     *            find method in this class
     * @param methodName
     *            find method with this name
     * @param parameterTypes
     *            find method with compatible parameters
     * @return The accessible method
     */
    public static Method getMatchingAccessibleMethod(final Class<?> clazz,final String methodName,final Class<?>[] parameterTypes){
        if (LOGGER.isTraceEnabled()){
            LOGGER.trace("Matching name=" + methodName + " on " + clazz);
        }
        final MethodDescriptor md = new MethodDescriptor(clazz, methodName, parameterTypes, false);

        // see if we can find the method directly
        // most of the time this works and it's much faster
        try{
            // Check the cache first
            Method method = getCachedMethod(md);
            if (method != null){
                return method;
            }

            method = clazz.getMethod(methodName, parameterTypes);
            if (LOGGER.isTraceEnabled()){
                LOGGER.trace("Found straight match: " + method);
                LOGGER.trace("isPublic:" + Modifier.isPublic(method.getModifiers()));
            }

            setMethodAccessible(method); // Default access superclass workaround

            cacheMethod(md, method);
            return method;

        }catch (final NoSuchMethodException e){ /* SWALLOW */ }

        // search through all methods
        final int paramSize = parameterTypes.length;
        Method bestMatch = null;
        final Method[] methods = clazz.getMethods();
        float bestMatchCost = Float.MAX_VALUE;
        float myCost = Float.MAX_VALUE;
        for (Method method2 : methods){
            if (method2.getName().equals(methodName)){
                // log some trace information
                if (LOGGER.isTraceEnabled()){
                    LOGGER.trace("Found matching name:");
                    LOGGER.trace(method2.toString());
                }

                // compare parameters
                final Class<?>[] methodsParams = method2.getParameterTypes();
                final int methodParamSize = methodsParams.length;
                if (methodParamSize == paramSize){
                    boolean match = true;
                    for (int n = 0; n < methodParamSize; n++){
                        if (LOGGER.isTraceEnabled()){
                            LOGGER.trace("Param=" + parameterTypes[n].getName());
                            LOGGER.trace("Method=" + methodsParams[n].getName());
                        }
                        if (!isAssignmentCompatible(methodsParams[n], parameterTypes[n])){
                            if (LOGGER.isTraceEnabled()){
                                LOGGER.trace(methodsParams[n] + " is not assignable from " + parameterTypes[n]);
                            }
                            match = false;
                            break;
                        }
                    }

                    if (match){
                        // get accessible version of method
                        final Method method = getAccessibleMethod(clazz, method2);
                        if (method != null){
                            if (LOGGER.isTraceEnabled()){
                                LOGGER.trace(method + " accessible version of " + method2);
                            }
                            setMethodAccessible(method); // Default access superclass workaround
                            myCost = getTotalTransformationCost(parameterTypes, method.getParameterTypes());
                            if (myCost < bestMatchCost){
                                bestMatch = method;
                                bestMatchCost = myCost;
                            }
                        }

                        LOGGER.trace("Couldn't find accessible method.");
                    }
                }
            }
        }
        if (bestMatch != null){
            cacheMethod(md, bestMatch);
        }else{
            // didn't find a match
            LOGGER.trace("No match found.");
        }

        return bestMatch;
    }

    /**
     * Try to make the method accessible
     * 
     * @param method
     *            The source arguments
     */
    private static void setMethodAccessible(final Method method){
        try{
            //
            // XXX Default access superclass workaround
            //
            // When a public class has a default access superclass
            // with public methods, these methods are accessible.
            // Calling them from compiled code works fine.
            //
            // Unfortunately, using reflection to invoke these methods
            // seems to (wrongly) to prevent access even when the method
            // modifer is public.
            //
            // The following workaround solves the problem but will only
            // work from sufficiently privilages code.
            //
            // Better workarounds would be greatfully accepted.
            //
            if (!method.isAccessible()){
                method.setAccessible(true);
            }

        }catch (final SecurityException se){
            // log but continue just in case the method.invoke works anyway
            if (!loggedAccessibleWarning){
                boolean vulnerableJVM = false;
                try{
                    final String specVersion = System.getProperty("java.specification.version");
                    if (specVersion.charAt(0) == '1' && (specVersion.charAt(2) == '0' || specVersion.charAt(2) == '1'
                                    || specVersion.charAt(2) == '2' || specVersion.charAt(2) == '3')){

                        vulnerableJVM = true;
                    }
                }catch (final SecurityException e){
                    // don't know - so display warning
                    vulnerableJVM = true;
                }
                if (vulnerableJVM){
                    LOGGER.warn("Current Security Manager restricts use of workarounds for reflection bugs " + " in pre-1.4 JVMs.");
                }
                loggedAccessibleWarning = true;
            }
            LOGGER.debug("Cannot setAccessible on method. Therefore cannot use jvm access bug workaround.", se);
        }
    }

    /**
     * Returns the sum of the object transformation cost for each class in the source
     * argument list.
     * 
     * @param srcArgs
     *            The source arguments
     * @param destArgs
     *            The destination arguments
     * @return The total transformation cost
     */
    private static float getTotalTransformationCost(final Class<?>[] srcArgs,final Class<?>[] destArgs){

        float totalCost = 0.0f;
        for (int i = 0; i < srcArgs.length; i++){
            Class<?> srcClass, destClass;
            srcClass = srcArgs[i];
            destClass = destArgs[i];
            totalCost += getObjectTransformationCost(srcClass, destClass);
        }

        return totalCost;
    }

    /**
     * Gets the number of steps required needed to turn the source class into the
     * destination class. This represents the number of steps in the object hierarchy
     * graph.
     * 
     * @param srcClass
     *            The source class
     * @param destClass
     *            The destination class
     * @return The cost of transforming an object
     */
    private static float getObjectTransformationCost(Class<?> srcClass,final Class<?> destClass){
        float cost = 0.0f;
        while (srcClass != null && !destClass.equals(srcClass)){
            if (destClass.isPrimitive()){
                final Class<?> destClassWrapperClazz = getPrimitiveWrapper(destClass);
                if (destClassWrapperClazz != null && destClassWrapperClazz.equals(srcClass)){
                    cost += 0.25f;
                    break;
                }
            }
            if (destClass.isInterface() && isAssignmentCompatible(destClass, srcClass)){
                // slight penalty for interface match.
                // we still want an exact match to override an interface match, but
                // an interface match should override anything where we have to get a
                // superclass.
                cost += 0.25f;
                break;
            }
            cost++;
            srcClass = srcClass.getSuperclass();
        }

        /*
         * If the destination class is null, we've travelled all the way up to
         * an Object match. We'll penalize this by adding 1.5 to the cost.
         */
        if (srcClass == null){
            cost += 1.5f;
        }

        return cost;
    }

    /**
     * <p>
     * Determine whether a type can be used as a parameter in a method invocation.
     * This method handles primitive conversions correctly.
     * </p>
     *
     * <p>
     * In order words, it will match a <code>Boolean</code> to a <code>boolean</code>,
     * a <code>Long</code> to a <code>long</code>,
     * a <code>Float</code> to a <code>float</code>,
     * a <code>Integer</code> to a <code>int</code>,
     * and a <code>Double</code> to a <code>double</code>.
     * Now logic widening matches are allowed.
     * For example, a <code>Long</code> will not match a <code>int</code>.
     *
     * @param parameterType
     *            the type of parameter accepted by the method
     * @param parameterization
     *            the type of parameter being tested
     *
     * @return true if the assignment is compatible.
     */
    public static final boolean isAssignmentCompatible(final Class<?> parameterType,final Class<?> parameterization){
        // try plain assignment
        if (parameterType.isAssignableFrom(parameterization)){
            return true;
        }

        if (parameterType.isPrimitive()){
            // this method does *not* do widening - you must specify exactly
            // is this the right behaviour?
            final Class<?> parameterWrapperClazz = getPrimitiveWrapper(parameterType);
            if (parameterWrapperClazz != null){
                return parameterWrapperClazz.equals(parameterization);
            }
        }

        return false;
    }

    /**
     * Gets the wrapper object class for the given primitive type class.
     * For example, passing <code>boolean.class</code> returns <code>Boolean.class</code>
     * 
     * @param primitiveType
     *            the primitive type class for which a match is to be found
     * @return the wrapper type associated with the given primitive
     *         or null if no match is found
     */
    public static Class<?> getPrimitiveWrapper(final Class<?> primitiveType){
        // does anyone know a better strategy than comparing names?
        if (boolean.class.equals(primitiveType)){
            return Boolean.class;
        }else if (float.class.equals(primitiveType)){
            return Float.class;
        }else if (long.class.equals(primitiveType)){
            return Long.class;
        }else if (int.class.equals(primitiveType)){
            return Integer.class;
        }else if (short.class.equals(primitiveType)){
            return Short.class;
        }else if (byte.class.equals(primitiveType)){
            return Byte.class;
        }else if (double.class.equals(primitiveType)){
            return Double.class;
        }else if (char.class.equals(primitiveType)){
            return Character.class;
        }else{

            return null;
        }
    }

    /**
     * Gets the class for the primitive type corresponding to the primitive wrapper class given.
     * For example, an instance of <code>Boolean.class</code> returns a <code>boolean.class</code>.
     * 
     * @param wrapperType
     *            the
     * @return the primitive type class corresponding to the given wrapper class,
     *         null if no match is found
     */
    public static Class<?> getPrimitiveType(final Class<?> wrapperType){
        // does anyone know a better strategy than comparing names?
        if (Boolean.class.equals(wrapperType)){
            return boolean.class;
        }else if (Float.class.equals(wrapperType)){
            return float.class;
        }else if (Long.class.equals(wrapperType)){
            return long.class;
        }else if (Integer.class.equals(wrapperType)){
            return int.class;
        }else if (Short.class.equals(wrapperType)){
            return short.class;
        }else if (Byte.class.equals(wrapperType)){
            return byte.class;
        }else if (Double.class.equals(wrapperType)){
            return double.class;
        }else if (Character.class.equals(wrapperType)){
            return char.class;
        }else{
            if (LOGGER.isDebugEnabled()){
                LOGGER.debug("Not a known primitive wrapper class: " + wrapperType);
            }
            return null;
        }
    }

    /**
     * Find a non primitive representation for given primitive class.
     *
     * @param clazz
     *            the class to find a representation for, not null
     * @return the original class if it not a primitive. Otherwise the wrapper class. Not null
     */
    public static Class<?> toNonPrimitiveClass(final Class<?> clazz){
        if (clazz.isPrimitive()){
            final Class<?> primitiveClazz = MethodUtils.getPrimitiveWrapper(clazz);
            // the above method returns
            if (primitiveClazz != null){
                return primitiveClazz;
            }
            return clazz;
        }
        return clazz;
    }

    /**
     * Return the method from the cache, if present.
     *
     * @param md
     *            The method descriptor
     * @return The cached method
     */
    private static Method getCachedMethod(final MethodDescriptor md){
        if (CACHE_METHODS){
            final Reference<Method> methodRef = cache.get(md);
            if (methodRef != null){
                return methodRef.get();
            }
        }
        return null;
    }

    /**
     * Add a method to the cache.
     *
     * @param md
     *            The method descriptor
     * @param method
     *            The method to cache
     */
    private static void cacheMethod(final MethodDescriptor md,final Method method){
        if (CACHE_METHODS){
            if (method != null){
                cache.put(md, new WeakReference<>(method));
            }
        }
    }

    /**
     * Represents the key to looking up a Method by reflection.
     */
    private static class MethodDescriptor{

        private final Class<?>   cls;

        private final String     methodName;

        private final Class<?>[] paramTypes;

        private final boolean    exact;

        private final int        hashCode;

        /**
         * The sole constructor.
         *
         * @param cls
         *            the class to reflect, must not be null
         * @param methodName
         *            the method name to obtain
         * @param paramTypes
         *            the array of classes representing the parameter types
         * @param exact
         *            whether the match has to be exact.
         */
        public MethodDescriptor(final Class<?> cls, final String methodName, Class<?>[] paramTypes, final boolean exact){
            if (cls == null){
                throw new IllegalArgumentException("Class cannot be null");
            }
            if (methodName == null){
                throw new IllegalArgumentException("Method Name cannot be null");
            }
            if (paramTypes == null){
                paramTypes = EMPTY_CLASS_PARAMETERS;
            }

            this.cls = cls;
            this.methodName = methodName;
            this.paramTypes = paramTypes;
            this.exact = exact;

            this.hashCode = methodName.length();
        }

        /**
         * Checks for equality.
         * 
         * @param obj
         *            object to be tested for equality
         * @return true, if the object describes the same Method.
         */
        @Override
        public boolean equals(final Object obj){
            if (!(obj instanceof MethodDescriptor)){
                return false;
            }
            final MethodDescriptor md = (MethodDescriptor) obj;

            return (exact == md.exact && methodName.equals(md.methodName) && cls.equals(md.cls)
                            && java.util.Arrays.equals(paramTypes, md.paramTypes));
        }

        /**
         * Returns the string length of method name. I.e. if the
         * hashcodes are different, the objects are different. If the
         * hashcodes are the same, need to use the equals method to
         * determine equality.
         * 
         * @return the string length of method name.
         */
        @Override
        public int hashCode(){
            return hashCode;
        }
    }
}
